An initial investigation has found that mechanical failure was likely not the cause of an air tanker crash Tuesday that took the life of 62-year-old pilot Geoffrey “Craig” Hunt.
That finding prompted the California Department of Forestry and Fire Protection to return its 22 Grumman S-2T planes to service Friday. The twin engine planes were grounded earlier this week after Hunt’s S-2T went down during a fire retardant application maneuver over the Dog Rock fire near Yosemite’s Arch Rock.
Cal Fire officials made the announcement at McClellan Airfield in Sacramento County, where the tankers are maintained. Officials said the planes would not immediately be used to fight the Applegate fire in Placer County, which grew to 459 acres Friday night.
Hunt’s plane flew out of Cal Fire’s base in Hollister. The agency has 13 bases spread throughout the state.
Cal Fire tankers have played a big role this year fighting blazes including the King fire, which scorched more than 97,000 acres near Highway 50.
On Friday morning, flags outside Cal Fire’s large service hangar at McClellan were flying at half-mast. Inside, Cal Fire and National Transportation Safety Board officials made their announcement in front of an S-2T.
“We’ve accounted for the majority of the airplane and right now we do not see anything that leads us to a mechanical-related issue with the accident,” said Josh Cawthra, aviation accident investigator with the NTSB.
Cawthra said that investigators examined the area by air and land but had limited access to the wrecked plane because it went down in an active fire area. Cawthra did not say what factors led the NTSB to conclude that mechanical failure was not at the root of the crash.
Of special concern was what may have happened to the left wing of the S-2T, which was found at the beginning of the quarter-mile-long wreckage area.
Hunt was flying an S-2T manufactured in 2001. The plane’s design is unusual in that it has wings that can be folded.
“From part of the wreckage signature that we’ve seen, we’re comfortable that it was not a mechanical issue,” Cawthra said.
The plane went down during the second pass of a fire area, after picking up 1,200 pounds of fire retardant at a Cal Fire base less than 20 minutes away. Cawthra said that there were no stress or mayday calls from Hunt before the plane crashed.
The NTSB will release the results of a preliminary investigation by the end of next week.
A full investigation will not be finished for at least six months and will likely take up to a year or more, Cawthra said. As a result, Cal Fire said that it would resume daily operations and activities with the 22 S-2T’s that the department purchased from the Navy in 1996.
However, the return of the planes to firefighting service depends on how comfortable pilots are with flying them while the investigation is still ongoing, said Daniel Berlant, Cal Fire spokesman. “We can rotate planes around here so that pilots that do not feel comfortable can fly other aircraft and fulfill our needs to have 22 pilots available today,” Berlant said.
The last time an S-2T went down was in 2001 when two air tankers collided in midair over Mendocino County.
The Cal Fire fleet is unique because most states don’t own and operate their own air tankers, Berlant said.
The S-2T is a single pilot plane that was initially designed by the Navy for use against submarines. When Cal Fire purchased 26 of the planes, they were outfitted with powerful turboprop engines. Some planes in that group have been used for parts and other services, Berlant said.